defmodule CustomerServiceWeb.ErrorJSON do
  @moduledoc """
  This module is invoked by your endpoint in case of errors on JSON requests.
  """

  alias Ecto.Changeset
  alias OpenApiSpex.Error

  def render("404.json", _assigns) do
    %{errors: %{detail: "Not Found"}}
  end

  def render("500.json", assigns) do
    detail = detailed_message(assigns[:reason], "Internal Server Error")
    %{errors: %{detail: detail}}
  end

  def render("400.json", assigns) do
    detail = detailed_message(assigns[:reason], "Bad Request")
    %{errors: %{detail: detail}}
  end

  def render("422.json", assigns) do
    detail = detailed_message(assigns[:reason], "Unprocessable Entity")
    %{errors: %{detail: detail}}
  end

  def render(template, assigns) do
    detail =
      detailed_message(
        assigns[:reason],
        Phoenix.Controller.status_message_from_template(template)
      )

    %{errors: %{detail: detail}}
  end

  defp detailed_message(nil, default), do: default

  defp detailed_message(%Changeset{} = changeset, _default) do
    format_changeset_errors(changeset)
    |> inspect()
  end

  defp detailed_message(%Error{errors: errors}, _default) do
    Enum.map_join(errors, ", ", fn e -> "#{e.code}: #{e.message}" end)
  end

  defp detailed_message(reason, _default) do
    inspect(reason, pretty: true)
  end

  defp format_changeset_errors(changeset) do
    Changeset.traverse_errors(changeset, fn {msg, opts} ->
      Enum.reduce(opts, msg, fn {key, value}, acc ->
        String.replace(acc, "%{#{key}}", to_string(value))
      end)
    end)
  end
end